The green and the brown: Coffee roasting at home
28. Oct, 2011 
7 Comments
It is one of my fundamental beliefs that most foodstuffs can be made successfully at home. The results may not be the best example of their type – there’s a reason specialist producers exist – but they are at least consumable and, with a little understanding of the physical and chemical reactions involved, often very good. Best of all, they teach you a lot about the process, giving you an appreciation for what makes the best examples so exceptional.
Still, there are a few products that I voluntarily exempt from my “DIY” approach. Wine is at the top of that list; wine grapes are so perishable, and the variables in making good wine so multifarious, that I think it’s better left to the experts.
For a while, I’ve vacillated on the question of home-roasting coffee. Partly because of the tangled web of fair-trade, organic and small-lot sourcing issues, which I’ve found intimidating. Partly because I didn’t want to invest in roasting equipment, and the low-cost techniques sounded like they had a longer learning curve without any guarantee of producing a decent result. And partly because I have access to a pretty darn good local roaster in Guelph, which I wanted to support. As far as I could tell, the best reason to roast your own coffee was that freshness is paramount in coffee, and there’s no way to tell how recently most commercially roasted coffee is. With access to a local roaster, this wasn’t a problem for me.
But there were some things that my local roaster couldn’t do. For one thing, I tend to favour African-grown coffees, and the only African coffees they carry are Ethiopian, which my husband doesn’t enjoy. For another, I find that Planet Bean’s roasts tend to be a little darker than I prefer, presumably to compete with other “second wave” roasters.
What sealed the deal was a visit with my friend Andy, who pointed out that I already have all the equipment I need to roast a preliminary batch: a bowl, a spoon, and a heat gun. Time to learn how this process worked.
Armed with some green coffee, Andy’s notes, and some online coffee-roasting references, I set to work: I put a half-pound of Kenyan beans into a stainless steel colander, grabbed a wooden spoon, an oven mitt and side towel, a sheet tray and my heat gun, and headed outside. (You want to roast coffee in a well-ventilated area, somewhere you don’t mind covering with chaff.)
The process essentially involves pointing the heat gun at the beans, stirring them, and waiting until they turn the shade of brown you’re looking for. I had read that the whole process should take about 20 minutes, but it took me a good deal longer than that: close to an hour. I suspect this was partly because I was overly cautious with the heat gun, it being my first attempt, and partly because the ambient temperature outside was so low. I also had trouble hearing the first crack, so I wasn’t sure that I had reached it. Eventually time pressure prevailed – I was already late for dinner with friends – so I spread the roasted coffee out on a sheet tray to cool, moved it and all my gear inside, and headed off.
The next morning, my husband (who gets up before me and almost always brews the coffee) ran some of the freshly roasted Kenyan beans through the grinder and brewed up a pot of French press. Much to my relief, it was actually pretty good! I may have a future as a home roaster yet.
The only major change I’ll make in my next effort is holding the heat gun closer to the beans and not stirring them as vigorously early in the process. I think my cautiousness contributed to the long total roast time, which in turn explains why the roast was not very dark. (Still, I was surprised at how even it was: all the stirring later in the process paid off.) Once I feel more solid on the fundamentals, I can start experimenting with blends, and with little tricks like roasting the same green beans to different roast levels, to customize the flavour.
If you’re a coffee lover with a heat gun and a source for green coffee, and you’re curious about what takes coffee from green to brown, you should give it a try!
Matthew Kayahara
I started with roasting coffee in my oven. This actually works pretty well, but can be smokey and messy. Still, I did quite a few batches like that. I mostly used a perforated pizza tray. Shake every few minutes. Then I went to an iRoast2 for a couple of years. It expired (due to me breaking the glass….), parts were not available and I wanted larger batches. Now I’ve been using a Behmor 1600 (from greenbeanery in TO) for quite a while and am extremely pleased. I also go for a medium to lighter roast for regular coffee (and only medium-ish for espresso) and love this roaster. The coffee is very good. So I’m warning you, it is a slippery slope
Paul, I have a friend who started with an iRoast2 and has since moved up to a 5-pound commercial “sample roaster,” so I had some sense of what a slippery slope it is when I started! And given how gadget-prone I am, it may be only a matter of time. Do you do a blend for your espresso, or single-origin? I’ll be curious to see if I can make an espresso blend I like.
I purchase a green blend for espresso. Currently I am using Sweet Santa from greenbeanery. I buy 10 lbs at a time, since that offers a good savings. Actually I’ve used regular coffee beans in my espresso quite a few times too, and it is quite good; of course, crema is different, etc. but the favour is good, just not quite the same as your regular espresso, particularly in NA where espresso tends to be very very dark and strongly flavoured.
Yeah, that’s a good point: I bought only small samples to try out the process, but if you can buy in bulk and save, that works great, since the green beans keep well. I’ve read conflicting opinions about single-origin espresso, and when I tried it with these beans I roasted, I didn’t love the outcome. Then again, there are so many variables with espresso that pinning it down on just the roast or the origin of the beans would take many shots!